Lever operated pin guided draw cut apparatus



Oct. 10, 1961 H. BlEL EI'AI.

LEVER OPERATED PIN GUIDED DRAW cu'r APPARATUS Filed Sept. 25, 1956 INVENTORJ. 77: 32's? 2 77.? ff'd'ffz BY w fl g "EA/2a I aw/vz'xfs:

United States Patent 3,003,381 LEVER OPERATED PIN GUIDED DRAW CUT APPARATUS Hans Biel and Ernst Pfiiflle, both of Neufien, Wurttemberg, Germany, assignors to Hans Sickinger, Providence Filed Sept. 25, 1956, Ser. No. 611,897

2 Claims. (Cl. 83-638) This invention relates to a cutting device for paper, cardboard or similar materials, wherein the cutting knife is arranged on a rocking knife holder.

Cutting. devices with rocking knife holders are known wherein the knife holder is guided by two non-parallel guide slots and connected by a thrust rod to the driving mechanism. In these known cutting devices the knife performs its cuts against a resilient base which has to be replaced after a certain number of cuts. Operation in conjunction with such a base requires that the knife be disposed parallel to the base at the end of its cutting stroke. The angle between the cutting edge and the plane of the material to be cut will therefore steadily decrease until the end of the cut so that the cutting edge may assume a parallel position at the end of the cut. As a result, the material to be cut will be squeezed rather than out toward the end of the cutting operation. Consequently, the machine will require considerably more power while the cutting edge of the knife is unevenly stressed and used to its disadvantage towards the end of cut.

It is an object of the present invention to provide a novel and improved cutting mechanism which has relatively low power requirements, insures a substantially even stress distribution along the cutting blade throughout the stroke, and is easily accessible for maintenance purposes. Other objects will become apparent in the following description and claims.

According to the present invention, the knife performs its cut against a stationary knife edge and the rocking motion of its holder is such that the angle of cut, while constantly varying, will not substantially vary from the original cutting angle during the entire pass along the stationary knife edge. In contrast to known cutting devices, a kind of drawing cut is performed during the entire cutting stroke. This will result in a constantly low power requirement and will avoid undesirable stress distributions along the cutting edge of the knife. After completion of the cut, the movable knife can be swung down until it is below the stationary knife edge. In this final position, the relative angularity of the knives will be of no further importance.

It is another feature of the present invention that the movable knife holder is linked to a rocker connected with the drive, while being guided at the same time by means of a stationary pin in conjunction with a slot to determine the cutting direction. Because of the arrangement of the rocker, the knife holder, when detached from the guide pin, may be swung 180 so that the knife becomes freely accessible for grinding or replacement, thus avoiding the necessity of removing the knife from the holder for grinding purposes.

Cutting devices are known wherein a movable knife is arranged at a cutting angle so as to cut against a stationary knife edge. In such devices however the knife holder is moved in a straight line at right angles to the plane of the material to be cut, so that it does not perform any rocking motion and therefore no drawing cut with subsequent low power requirements. The satisfactory and even cutting stroke and the low power requirements of the present invention are achieved by the coaction of the rocking motion of the knife holder and the stationary knife edge.

The invention is described by an embodiment which is for the most part schematically illustrated in the drawing, wherein:

FIGURE 1 is a side elevational view of the movable knife holder, in which the lowermost position of the knife holder as well as various intermediate positions of the knife edge are marked in a dot-and-dash pattern, while the knife holder as it is swung out for grinding or replacement of the knives is shown in dotted lines; and

FIGURE 2 is a sectional view taken along the line 22 of FIGURE ,1 and showing the relationship between the movable :and stationary, knives.

A movable cutting knife 1 is fastened in a suitable manner to a flat holder 9 which may be moved in a vertical plane between guides 6, 7. The knife holder has a pivotal connection 2 at one end to a rocking arm 4 which may be swung by a driving mechanism such as a reversible electric motor and gear reducer 112 about a pivoted drive shaft .11 between the positions shown in solid and dotdash lines. It will be noted that rocking arm 4 is inclined upwardly in the direction from pivot 11 to pivot 2 when the holder is in its uppermost or solid line position. Near its other end the knife holder is provided with a guide slot 3 within which is disposed a stationary pin 5. Slot 3 is inclined downwardly and away from pivot 11 at an acute angle to the plane of the material to be cut. This angle may vary between 30 and 70 degrees. Cutting knife 1 is so arranged on the knife holder that when the latter is at the top of its stroke, as shown in solid lines in FIGURE 1, the knife is positioned at an acute angle to the horizontal plane or plane of the material to be cut.

Rocking arm 4 is adapted of move knife holder 9 between the various positions shown in solid and dot-dash lines in FIGURE 1. During this movement, the knife holder performs a rocking motion during which the angle of the movable knife with respect to the stationary knife is varied in that it decreases towards the lower end of stroke. It will be noted from an examination of the various dot-dash positions in FIGURE 1 that the variation in angularity of knife 1 will be relatively slight during the major portion of its stroke, most of the rocking motion occurring toward the bottom of the stroke.

Knife 1 cuts against a stationary bottom knife -8. This is arranged at such a height that the edge of knife 1 moving toward its lower limit position will entirely pass stationary knife 8, during which passage knife 1 will form an angle that dew'ates only slightly from the original cutting angle with respect to knife 8. This arrangement ensures a drawn cut during the entire passage of knife 1 along the edge of the stationary knife 8. It is only after knife 1 has passed knife 8 that the relative angularity of the knives will decrease, as shown by the final dotdash position of FIGURE 1.

Through loosening of a locking arrangement, such as a key 13 between shaft 11 and arm 4, rocking arm 4 may be swung out beyond its topmost operating position, which is shown in FIGURE 1, into a horizontal position together with the knife holder, so that the knife will point upwards behind the place of cut (dotted position, see FIGURE 1) in order to render it accessible for regrinding or replacement. To be swung out, the knife holder must at the same time be detached from the guide pin 5. This is most easily accomplished if slot guide 3, as shown, is open at its lower end.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

said stationary knife, the movable knife being movable between open and closed positions with respeet to said stationary knife, a holder for said movable knife having a slot in one end thereofisaid' slot being disposed at an acute angle lying between said predetermined angle and a 90 angle with respect to said stationary knife," a stationary guide pin circular in cross section disposed in said slot, an arm oscillatable on a stationary axis between the opened and closed positions of the movable knife, and a pivotal connection between the outer end of said movable arm and the end of said holder remote from said slot, the relative positions ofsaid' stationary axis and movable knife in the opened position of said movable knife further being such that the path of movement of saidpivotal connection will be more steeply inclined than said slot with respect to: the stationary knife after said movable knife has passed its closed position, whereby the relative angle between said stationary and movable knives will be decreasedafter the work has been cut.

on said pivotal connection after said slot has beenremoved from said pin to permit. access. to said knives;

References Cited in the file of this. patent UNITED STATES PATENTS 15,069 Dole June 10, 1856 1,343,079 Fegley et al. June 8, 1920 1,413,206 Tyler Apr, 18,, 1922 1,609,365 Knott Dec. 7, 1926' 1,678,080 Renz July 214, 1928 FOREIGN PATENTS 584,023 Germany Sept. 27, 1933 887,489 Germany Aug: 24', 1953' 

